Why a NAS drive and not a desktop drive
A NAS runs 24 hours a day, with several drives vibrating together and RAID rebuilds that read the whole disk. NAS-class drives are built for that: firmware that handles errors without dropping the drive from the array, better vibration tolerance and 3 to 5 year warranties. Desktop drives are cheaper but not designed for RAID.
| Range | Recommended bays | Warranty | When to choose it |
|---|---|---|---|
| WD Red Plus | Up to 8 | 3 years | Home or small office NAS |
| Seagate IronWolf | Up to 8 | 3 years | Home NAS; includes a data recovery service |
| Toshiba N300 | Up to 8 | 3 years | 7200 rpm alternative |
| WD Red Pro / IronWolf Pro | Up to 24 | 5 years | Heavy use, business or many bays |
How to read the table
All four ranges use CMR recording and are designed for RAID. The practical differences are how many drives the enclosure takes, the warranty and noise: 7200 rpm models are a little faster but also louder and warmer, worth considering if the NAS sits in the living room. For home use any of the first three is a good choice; the Pro ranges pay off when the NAS works non-stop or has more than 8 bays.
CMR versus SMR: what matters most
SMR recording overlaps tracks to gain capacity, but writes much more slowly when the drive is busy. In a RAID, a rebuild with SMR drives can take days or even fail. Some desktop drives and the older WD Red without «Plus» use SMR.
Before buying, check on the spec sheet that the drive is CMR. The ranges in the table are CMR across their current capacities.
Which capacity to buy
First work out the space you need and add headroom for two or three years. Then choose the RAID level: 2 drives in RAID 1 give you the capacity of one; 4 in RAID 5 give you three. The RAID calculator gives you the exact usable capacity.
In price per TB, 8 to 12 TB drives usually beat small ones. With very large drives rebuilds take longer, so with 4 bays or more consider RAID 6 or SHR-2.
Noise, power and temperature
5400 rpm drives are quieter and use a little less power; 7200 rpm drives perform better on random access. On a home NAS connected at 1 Gb/s the network limits speed before the drive does, so favour quiet drives if the NAS is nearby.
Each drive draws roughly 4 to 8 W. With the electricity consumption calculator you can see what it costs to keep the NAS on all year.
How many drives and which RAID
With a 2-bay NAS the usual choice is RAID 1 or SHR with two identical drives: if one fails, you lose nothing. With 4 bays you have more options: RAID 5 makes better use of space, RAID 6 or SHR-2 survive two failures and RAID 10 is faster. If you start with two drives in a 4-bay NAS, leave room to grow: many NAS units let you add drives and expand the volume later.
How to buy without mistakes
Compare price per TB, not just the price of the drive. Check that it is sold by Amazon or a trusted seller and that it is a product for your region, because some warranties depend on the country of sale. Keep the invoice and register the serial number on the maker website: if the drive fails under warranty, the replacement will be quicker.
Common mistakes
Reusing old drives of different sizes: the RAID shrinks to the smallest one. Not checking new drives: test their SMART status when you install them. And above all, thinking RAID is a backup: it is not, always keep a separate copy.
Frequently asked questions
Can I mix drives from different brands?
Yes, as long as they have the same capacity and are CMR. Mixing brands or batches even lowers the risk of them failing at the same time.
Can surveillance drives be used in a NAS?
They are designed for continuous video writes, not the mixed access of a NAS. They can work, but it is better to use each range for its purpose.
How many years does a NAS drive last?
Many last more than 5 years, but nothing is guaranteed. Watch the SMART alerts of your NAS and keep a spare drive if you store important data.
Do I need drives with a 5 year warranty?
At home it is usually not necessary: 3 years is enough for most people. A 5 year warranty pays off for businesses or for a NAS that works non-stop, because it lowers the cost of replacing drives that fail later on.